In a binary geothermal electric production facility, the hot water or steam is passed through a heat exchanger, where it heats a second liquid—such as isobutane—in a closed loop. The isobutane boils at a lower temperature than water, so it is more easily converted into steam to run the turbine generator. One of the most problematic issues facing hydrothermal energy production is the precipitation of mineral elements during the cooling process. This extraction of heat from hot hydrothermal fluids or steam (i.e., cooling and transfer of heat), often results in precipitation of substances which clog the system. Heat exchangers, by their very nature, call for high physical exposure of metal tubing to the geothermal hot water and steam which can be easily clogged by such precipitates, causing downtime, unreliability, and higher cost of capital due to this inherent and oftentimes unpredictable nature of transformation.
Hot geothermal gases of either mesothermal or epithermal origin contain REEs and HEs. REEs predominantly occupy the Lanthanide or Actinide series of the Periodic Table of Elements, and are present, to some degree, in hot geothermal hot water and steam used to generate electricity. HEs are many of the transition elements of the periodic table and some metalloids. Many of these trace elements are essential, even in small amounts, as catalysts, in electronics and other applications. The literature indicates that the global markets are running low on REEs and HEs and rare elements of all types.
Known methods for separating REEs from other components utilize horizontally mounted drums with a magnetic field. A belt is placed over the drum and the level of paramagnetic susceptibility of various REEs and HEs provide that various REEs and HEs drop from the belt purely from the normal force of gravity as the belt passes over the magnetic drum, the more paramagnetic elements holding to the belt as the belt passes away from the magnetic drum thus causing separation by paramagnetic properties. In another technology, the subject particles are deposited directly on the magnetic drum and a similar separation process occurs.
A major drawback of these technologies is the magnet also collects dust which causes the process to be very expensive including the need to remove dust prior to the use of these technologies. A drawback using the belt-based technology is that the belts need to be frequently replaced meaning that the cost of replacement raises the cost of operation by more than 50% over non-belt-based applications.